Electrostatic separator.



PATENTED AUG. 7,. 19661 M. WQDSM'B.

BLBGTROSTATIG SEPARATOR.

Apenmnmn funn JAN. 2a, naar= SVENTBQ UNITED PATENT OFFICE.

MILLARD WOODSOME, OF BOSTON, MASSACHUSETTS, ASSIGNOR- TO H UFFELECTROSTATTC SEPARATOB COMPANY, OF BOSTON, MAS- SACHUSETTS, ACORPORATION OF MAINE.

' ELEGTROSTATIG SEPARATOR.

Speccation of Letters Patent.

:Patented Aug. 7, ieee.v

Application filed January 29, 1906. Serial Nox 298.382.

To @ZZ-107110791, it may concern.-

Be it known that I, MiLLARD WooDsoME,

va citizen of the United States, and a resident ments hereinbelow to bedescribed whereby.

the electrical conditions at the separator-electrodes are improved andthe contrast in electrical condition of those portions of therepelling-electrode which are immediately opposed tothe oppositeelectrode in relation to such portions as are not so immediately opposedis enhanced.

In the drawings hereto annexed, which illustrate an embodiment of myinvention and improvements,y Figure 1 is a vertical cross-section oi theentire machine, taken at the line 1 1 of Fig. 2; and Fig. 2 is a sideelevation of the same, one of the sides of thev casing thereof beingremoved.

The source of electrical energy whereby the electrostatic separator isexcited is not herein shown. 'Anv desired exciting devices may beemployed; but l prefer to use the electrical machinery which is shownand described in its essential com onents in United StatesLetters Patento. 796,011, dated August 1, 1905, issued to Charles H.

,Huit as assignee of Greenleaf W. Fickard.

The casing A is a rectangular box of conductive material composed,preierablyo f` sheet iron or steel, with a suitable,` angle-'ironJframe. This case is mounted upon insulating-supports B, which varepreferably oi earthenware orporcelain orv which may under someconditions be'c'omposed of wood. Upon the top of the casing A there ismounted the hopper C, into which the material to be fed tovthe`separator-electrodes is deposited. The hopper C terminates in adelivery-chute composed of two parallel plates D D', which areconstructed ot electricallyconducting material, preferably sheet-steel.Four sets of electrodes are shown in the drawings, each set consistingof a pairnamely, the large metallic rotary electrode E and a gridiion otstationary electrodes E',

the latter consisting, preferably, of small copper wires, each inclosedin a thick glass tube. The electrode E of each pair is a metalliccylinder having, by preference, a brass or copper surface, which maybeof sheet vmetal or be electroplated upon an iron roller.

The electrodes E are rotatively mounted in the ends of the casing, as atM, and are provided with suitable mechanism (not shown) for giving theelectrodes E a rotary movement, (indicated by arrcws,) so as to carrymaterial fed thereto from the hopper C to'- ward the electrode E'. Theelectrode E'- that is to say, the group of glass-insulated copperwires-is sustained by the casing, the ends N of the glass tubes passingthrough suitable perforations in the end walls of the -casing A. All ofthe electrodes E are c'onnected withv onepole of the generating orexciting mechanism, as by a'wire P, andthe ends@ all therelier-electrodes E are connected, as by a wire O, with the oppositepole or terminal of the exciting mechanism. Upon suitable metallic clipsF2, secured tO vtheinside of the end walls of .the casing A,

there are mounted the inclined plates F, F', and G', the plates F beingcontinued upwardly and then inwardly toward the electrode E, wheretheyprovide a proper mounting for the wipers K. The plates F, F', and Gare composed oi metal, preferably sheetsteel, and the lower set ofplates F and F terminate in plates H and H', while a sheetmetal plate H2extends downward, converging toward .the plate H' from the side of thecasing A. In the bottom of the a paratus there are shown. spiralconveyers I Y', are rotatively mounted and serve to convey the separatedmaterials endwise of the case to suitable points of delivery.

The plates F, F', G, D, and D' are all in electrical metallic contactwith the casing A and aretherefore in parallelelectrical communicationwith' the electrodes E and the terminal of the exciting apparatus (shownconventionally at x, Fig. 2) to which the wire O leads, (and also thewire 1),) While the electrode E' is insulated from the rest of theapparatus. These plates, taken collectively, form an electric shield orinclosure around those parts of the repelling-electrode E which are notin immediate opposition to the opposed elecwhich 4 IOO trode E', solthat these plates constitute in substance an inclosing case or box forthe rotary electrode. The lines of force established between the twoelectrodes roceed directly from the electrode E to the e ectrode E inthe region of their greatest density, but indirectly from the lates D,D,"F, F, and G to the electrode E the density of lines of force isleast, and that portion of the surface of the re elling-electrode Ewhich is inclosed by this metallic sheath is electrostatically shieldedfrom the electrode E and is therefore electrically inert, and thus inits electrical condition is much more sharply contrasted with theelectrical condition of that portion which isimmediately opposed to theelectrode E than has heretofore been the case when the electrode E orits equivalent has not been inclosed in any electrically-active sheath.

In the construction herein shown there is provided a series of electrodepairs E E', to which the material is conducted in vertical succession,the lower pairs of electrodes in the series serving to supplement theseparation accom lished by the-first ,air. Thus the plates Fl? F, and Gin this em odiment of my invention are made to perform a mechanical aswell as an electrical function in that the plate G diverts the heads ofthe separate material into one region in the casing, While the lates Fand F collect the tails which fall rom the surface of the electrode E orare brushed therefrom by the wipers K and deliver them at the narrowchutes formed by the lower edges F F of these plates to the nextsucceeding electrode.

By the means above described the heterogeneous material delivered to thesurface of the rotary repelling-electrodes E is subjected to the fullseparative effect of the electrical field While it is passing throughthat region which lies immediately opposed to the electrode E; but inits further progress that portion of the material which has not been repelled while passing through this region goes into an inclosed space,wherein no electrical@ excitation is manifested, this inclosed spacebeing, in eect, the interior of'a hollow conducting-body Within which,however great the external excitation may be, no electrical charge canpenetrate. 1t has been observed in actual practice that, other thingsbeing `equal and other conditions remaining the same, a more effectiveseparation of materials is accomplished with the designedly inactiveareas of the .re elling-electrode inclosed by an electrical y-conductingshieldV om those regions where than when these improvements are notemployed.

What I claim, and desire to secure by Letters Patent, is-

1. `In an electrostatic separator, the combination of arepelling-electrode, means to feed material thereto, an opposedelectrode, electrical exciting mechanism and connections therefrom tothe electrodes, and an electrostatic shield inclosing and shieldingportions of the repelling-electrode which are not in immediateopposition to the opposed electrode.

2. In an electrostatic separator, the combination of arepelling-electrode, means to feed material thereto, an opposedelectrode, electrical exciting mechanism and connections therefrom tothe electrodes, and an electrically-conducting shield, surroundingportions of the repelling-electrode which are not in immediate oposition to the opposed electrode, said s ield being electricallyconnected with the exciting apparatus in parallel with therepelling-electrode. I 3. In an electrostatic separator, the'combination of a repelling-electrode, an opposed electrode, means tofeed material to the el'ectrode including a metallic delivery-chute,metallic lates to distribute separated products, sai plates surroundingportions of the repelling-e ectrode which are not in immediateopposition to the opposed electrode, and electrical exciting mechanism,with connections to the electrodes and to the metallic delivery-chuteand distributing-plates, the chute, plates, and repelling-electrodebeing connected to the same terminal of the exciting mechanism.

4. in an electrostatic separator, the combination of a metallic casing,insulating-supports therefor, a repelling-'eleotroda an oppositeelectrode, a hopper, a metallic delivery-chute therefor to delivermaterial to the repelling-electrode, a metallic shield r'ote'cting suchportions of the repclling-e ect'rode as are not in immediate oppositionto the opposite electrode, the repelling-electrode, hopper-deliverychute, and shield being within and in electrical contact with thecasing, and electrical exciting mechanism and connections therefrom tothe several electrodes.

Signed by me at Boston, Massachusetts, this 24th day of January, 1 906.

MILLARD VOODSOME.

Witnesses:

JOSEPH T. BRENNAN, C. D. WOODBERRY.

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